This invention relates to a ventilation system for a vehicle. More specifically, the invention relates to a ventilation system, which is capable of actively or passively moving air between the upper region of the interior of the vehicle and the atmosphere outside the vehicle as well as circulating air within the upper region of the interior of the vehicle. The ventilation system is capable of actively moving air between the interior of the vehicle and the outside atmosphere whether the vehicle is stationary or moving. The ventilation system is also capable of actively or passively moving air between the interior of the vehicle and the outside atmosphere in rainy weather while preventing the entry of moisture through the ventilation system into the interior of the vehicle.
In vehicles which have occupant cabins with high ceilings and heating ventilation and air conditioning (HVAC) systems with supply and return ducts concentrated near the lower portion of the occupant cabin, there is generally very little circulation or replacement of the air in the upper portion of the occupant cabin. Thus, it is often the case that the vehicle""s HVAC system is not capable of rapidly effecting and maintaining a comfortable environment in the upper portion of the occupant cabin. When the vehicle""s air conditioner is operated, the warm air in the upper portion of the vehicle interior is slow to mix with the cool air introduced into the lower portions of the occupant cabin by the vehicle""s air conditioning system. Furthermore, because there is very little replacement of the air in the upper portion of the vehicle""s interior, it can stagnate and become stale.
There exist a few designs, which aim to improve the condition of the environment in the upper portion of the occupant cabin. One such design is the inclusion of vent windows in the upper portion of the exterior structure of the occupant cabin to allow for fluid communication between the interior of the occupant cabin and the outside atmosphere when the vent windows are open. While this system allows for ventilation of the upper portion of the interior of the occupant cabin, it can not be utilized in rainy weather without introducing moisture into the interior of the occupant cabin. U.S. Pat. Nos. 5,779,536 and 6,004,202, disclose a design which has a ventilating duct with an inlet adjacent the ceiling of the vehicle interior and an outlet to the outside atmosphere near the floor of the vehicle interior. This design allows air to move between the upper portion of the interior of the vehicle and the atmosphere outside the vehicle. The design relies on positive cabin pressure, which is only achieved when the vehicle is moving forward, to actively move the air between the upper portion of the interior of the vehicle and the atmosphere outside the vehicle. Other systems disclosed in U.S. Pat. Nos. 4,189,987 and 5,081,912 and 5,690,549 show ventilation systems which are mounted to the roof of a vehicle""s occupant cabin and have fans for actively moving air between the interior of the occupant cabin and the outside atmosphere.
As a result,xe2x80x94an object of the present invention is to provide a ventilation system 10 which is capable of actively or passively moving air between the upper portion of the interior 11 of the occupant cabin 12 and the outside atmosphere 13, whether the vehicle is stationary or in motion, under any weather conditions, without allowing the entry of moisture through the ventilation system 10 into the interior 11 of the vehicle.
The present invention is a ventilation system 10 for mounting to an upper portion of the exterior structure 14 of a vehicle""s occupant cabin 12. One or more components 15 of the exterior structure 14 of the occupant cabin 12 define an opening 16 through the upper portion of the exterior structure 14 of the occupant cabin 12. Air can move through this opening 16 from the interior 11 of the occupant cabin 12 to outside the occupant cabin 12 and vice versa. A duct 17 is mounted to the vehicle. An outer wall 18 of a first end 19 of the duct 17 is mated to an outer surface 20 of one or more components 15 of the exterior structure 14 of the occupant cabin 12. The outer wall 18 of the first end 19 of the duct 17 surrounds at least a portion of the opening 16 in the exterior structure 14 of the occupant cabin 12. Thus the interior 21 of the duct 17 is in fluid communication with the opening 16 in the exterior structure 14 of the occupant cabin 12. A second end 22 of the duct 17 is positioned at a point below the first end 19 of the duct 17 and is open to, and in fluid communication with, the outside atmosphere 13. The ventilation system 10 has a fan 23, which is mounted to the vehicle. The fan 23 is mounted at a position such that either the inlet area 24 or the outlet area 25 of the fan 23 is located near, and is in fluid communication with, the opening 16 in the exterior structure 14 of the occupant cabin 12.
Thus the ventilation system 10 of the present invention accomplishes all of its objects. The fan 23 of the ventilation system 10 can be used to actively move air from the upper portion of the interior 11 of the occupant cabin 12, through the ventilation system 10, and into the outside atmosphere 13. This mode of operation of the ventilation system 10 is shown in FIG. 1. If the fan 23 is made to move air in the reverse direction the ventilation system 10 can move air from the outside atmosphere 13, through the ventilation system 10, and into the upper portion of the interior 11 of the occupant cabin 12. When the fan 23 is not in operation the ventilation system 10 passively moves air between the outside atmosphere 13 and the interior 11 of the vehicle""s occupant cabin 12. Because the second end 22 of the duct 17 is positioned below the first end 19 of the duct 17, moisture is prevented from entering the interior 11 of the occupant cabin 12 through the ventilation system 10.